diff --git a/test/ruby/test_syntax.rb b/test/ruby/test_syntax.rb
index f2b42d8a3b..2877491cdc 100644
--- a/test/ruby/test_syntax.rb
+++ b/test/ruby/test_syntax.rb
@@ -330,7 +330,7 @@ eom
   def not_label(x) @result = x; @not_label ||= nil end
   def assert_not_label(expected, src, message = nil)
     @result = nil
-    assert_valid_syntax(src, message)
+    assert_nothing_raised(SyntaxError, message) {eval(src)}
     assert_equal(expected, @result, message)
   end